Method of and apparatus for internal gear shaving



April 5, 1960 R. M. WILLIAMS 2,931,274

METHOD 0F AND APPARATUS FOR INTERNAL GEAR SHAVING Filed Hay 28, 1956 2Sheets-Sheet 1 FIG.I.

INVENTOR.

ROBERT M .WILLIAMS M/MM2, @M9/MTC R NEYS Ap s, 1960 R- M MU-MS 2,931,274

METHOD 0F AND APPARATUS FOR INTERNAL GEAR SHAVING Filed lay 28. 1956 2Sheets-Sheet 2 Om Nm INVENTOR.

ROBERT M. WILLIAMS Y Ww,

ATTORNEYS United States Patent() 1 2,931,274 METHOD F AND APPARATUS FORINTERNAL GEAR SHAVING Robert M. Williams, East Detroit, Mich., assignerto National Broach & Machine Company, Detroit, Mich.,

a corporation of Michigan Application May 28, 1956, Serial No. 587,82911 Claims. (Cl. 90-1) The present invention relates to internal gearshaving.

It is an object of the present invention to provide a method andapparatus for facilitating the finishing of internal gears, and moreparticularly for permitting semiautomatic loading.

It is a further object of the present invention to provide in a machinefor finishing internal gears, means to facilitate placing an internalgear on a gear-like finishing tool, thereafter advancing the tool withthe internal gear therein into a pot chuck, and finally clamping theinternal gear in the chuck in meshed relation with the tool.

More speciiically, it is an object of the present invention to provideapproximate locating mechanism in association with a support for agear-like cutter which permits positioning of an internal gear on thecutter in approximately located position for insertion into a pot chuck.

lt is a further object of the present invention to provide in mechanismas described above, locating fingers adapted to extend loosely within aninternal gear to prevent rocking of the gear on the gear-like tool, thepot chuck including clamping mechanism adapted to move the gear out ofcontact with the fingers.

It is a further object of the present invention to provide a pot chuckfor receiving an internal gear approximately located in meshed relationon a tool in the form of an external gear, said chuck including clampingmeans adapted to shift the gear relative to approximate locating meansassociated with the tool into clearance position for free running.

It is a further object of the present invention to provide in a potchuck, ejector pins, clamp means, means for actuating the clamp means torelease the gear and simultaneously to actuate the ejector pins to pushthe gear out of the chuck, and springs for receiving and supporting theejected gear at the front of the chuck.

Other objects and features of the invention will become apparent as thedescription proceeds, especially when taken in conjunction with theaccompanying drawings, wherein:

Figure l is a side elevational View partly in section, of an internalgear finishing machine.

Figure 2 is an enlarged front elevational view of a pot chuck.

Figure 3 is an approximately horizontal sectional view taken on the line3-3, Figure 2, and showing the approximate locator mechanism inposition.

Figure 4 is a side elevational view of the approximate locatormechanism.

Figure 5 is a fragmentary front elevational view of a portion of theapproximate locator mechanism.

Referring first to Figure l, the present invention relates to aninternal gear finishing machine of the type comprising a main frame 1i)having a vertically movable knee 12 mounted thereon in vertical waysprovided with means for effecting vertical movement of the kneeincluding the feed screw 14. The gear finishing machine includes worksupporting mechanism indicated generally at 16 which includes spindlemeans 1S adapted to be driven in rotation by a motor (not shown) andhaving at its ends a pot chuck indicated generally at 20.

Mounted on the knee 12 is a tool slide 22 mounted for horizontalmovement toward and away from the open Fice end of the chuck 20.Preferably, suitable means are provided for effecting a substantialmovement of the tool slide to effect wide separation between thegear-like iinishing tool T and the internal work gear G suitably clampedin position within the chuck 20. In addition, when the gear is clampedin position in the chuck and the tool T is in mesh therewith the cutterslide 22 is reciprocated slowly to effect a feeding movement parallel tothe axis of the gear G. The tool spindle 24 is mounted for free rotationand the tool T is rotated by virtue of its meshing engagement with thegear G, which is positively driven in rotation.

In this type of machine considerable difficulty is encountered ineecting rapid loading and meshing of the cutter and gear after loading.

The usual manner of loading ya series of Work gears in an internal gearfinishing machine of the type disclosed herein was to withdraw thecutter slide 22 substantially from the work supporting chuck to giveworking room for loading the gear into the chuck. Thereafter, the gearwas moved into the chuck and clamped therein by suitable means (notshown in this figure) Thereafter, it was necessary to advance the toolslide to cause the tool T to move into meshed engagement with the gearG. This of course required exact angular location of the tool relativeto the gear and required the operator to move the tool slowly intoposition to avoid possible damage if thev ends of the cutter teethengaged the ends of the gear -teeth.

It will of course be appreciated that in Figure 1 for simplicity thegear and tool are both shown with their axes parallel. In practice, thenishing operation is normally carried out with a gear-like shavingcutter having gashed teeth providing cutting edges extending in planesperpendicular to the axis of the cutter, and the cutter is designed tomesh with the gear with the axes of the gear and cutter crossed at asubstantial angle las for example between 3 degrees and 30 degrees. Itwill also be appreciated that in use it is normal for the knee 12 to beraised to a position such that the cutter is in mesh at the upper sideof the gear G.

Referring now to Figures 2-5 there is illustrated the mechanism whichgreatly facilitates loading of the internal gear finishing machine.

In accordance with the present invention there is provided a special potchuck designated 30 having therein a locating adaptor 32 designed forthe particular gear being finished, the gear being shown at G. The chuck30 is rigidly supported at the foreward end of the work driving spindle34 and associated therewith is a drawbar 36 having a head 38 rigidlysecured thereto. The head 38 includes an annular ange 39 to which isbolted or otherwise secured plates 40 having notched ends 42 fittingwithin annular grooves 44 in clamp elements 46. The clamp elements 46have laterally extending clamping portions 4S adapted to overlie theouter end of the annular gear G and to clamp it firmly against alocating shoulder 50 located in the adaptor 32. The clamping elements 46are longitudinally slidable in aligned cylindrical holes 52 in the chuckand are provided with pin receiving slots 54 adapted to receive guidepins 56. The slots 54 include straight portions and also inclinedportions so that as the clamping element 46 is moved to the right fromthe position shown, it flrst moves out in a straight line and thereafterits further travel is accompanied by angular movement which moves thelaterally extending clamping portion 48 into a clearance position withrespect to the work gear G.

The adaptor 32 is also provided with a plurality of pin receivingopenings 58 which receive ejector pins 60 in position to be engaged bythe ange 39 of the head 38 connected to the drawbar.

i' The fixture or adaptor 32 is also provided with a plurality' oflretainer springs 62 which are adapted to engage and support a work gearG when it is moved to the Vright from its illustrated position by theejector pins 6,0. This The spindle 64 is mounted in a cutterspindlehousing atY the forward end of which is provided an end plate 66;

f Secured to theY end plate 66is an annular adaptor 68 Y which surroundsthe forward end of the tool spindle and which is provided with an kendface 70 confronting the chuck 30, the end face being perpendicular tothe axis thereof. Fastened to the end faceV 70 of the adaptor 68 isY theapproximate locator 72, the attachment means being` suggested in Figure3 asY comprising screws 74.

The approximate vlocator 72, as best seen in Figures 4 and 5, may begenerally of semi-circular shape and dimensoned to surround the'forwardend of the to'ol spindle 64. Extending forwardly and parallel to theaxis of the gear G are a pair of locating ngers 76. These ngers aredesigned to extend within the work gear G withY a certain amount oflooseness so as to preventv rocking'movement of the gear G when it isplaced in meshing relation on the cutter or tool T while the tool is inits retracted position remote from the chuck 30. In Figure 4 therelationship of parts is well illustrated, the fingersr76 extending iforwardly at opposite sides of the tool T. In thisv gure a portion ofthework gear G is illustrated belowthe tool T and having its inner surfaceengaged with a light'spring 78 having its forward end inclined asillustrated to facilitate movement of the gear Vinto position with theVteeth at the top thereof in mesh with the teeth at the top of the tool Tand with the teeth at the-'bottom thereof engaged by the spring 78.

With the parts as described, the operation is believed apparent but willbe briey reviewed. In the first place the operator upon completion of agear finishing operationtcausesthe cutter slide to move ksubstantiallytothe right from the position Yshown in Figure 3, to withdraw the cutterto a position completely removed from the chuck 30. Advancement of thedrawbar 36 releases the work piece Yin the chuck, movesV the clampingelements146 outwardly androtates the clamping portions 48 thereof intoclearance position. Final movement of the drawbar to the right, as seenin thergure results in forward movement of the ejector pins 6,0 whichreleases the'gear G from the chuck and leaves it supported on therelatively light springs 62; Y

TheV operator now manually removes the iinished gear from the springs62. He then places an unfinished gear manually in position on the gearshaving toolV and moves it toV a position in which its lower teeth movebeneath the spring 78. This supports the unnished gear on Ythe cutterfor further movement. In addition, this assembly of' the unfinished gearon the tool results in placement of theV gear in such away that thelocating lingers 76 extend within the gear. These fingers are designedto have appreciable clearance with respect to the innerV ends of thegear teeth andare for the purpose' of'preventing rocking movement of thegear; So long as the-gear is" 78, the gear Y firmly retained on thecutter by the spring need' never contact the locating fingers 76;

With the gear in properly meshed relation on the'cutter,V the cutterslide isV now movedtoward the chuck to' aposition in which the gear ispartly received within the chuck.Y

At'tln's timeV however, forward movement'ofthe toolY slide Y is: to theapproximateposition shown in'yFi'gu'r' 3,' whichY l'eaVesJthel spring.".78w substantially outside.' the chuck.n Af this time the drawbar isretrajcttedwhich-results-in:nist

Vat a definite angle with respect to the axis of 'the' gearG. l

rotating the clamping portions 48 of the clamping elements 46 to aposition in which they overlie the end of the gear and thereafter inaxial movement of the clamping elements to shift the gear. to .theposition illustrated in Figure 3k againstthe locating shoulder 50whereit is firmly clamped in position. The drawbarmay be actuated bysuitable Vmeans such for example as an air cylinder (not shown).Y f

i It will be observed that actuation of the clamping elementshas theeffect of shifting the gear away from the approximate locator althoughnot sufliciently to move it out of mesh with the gear-like tool T. Thegear is thus moved away from VVthe spring-78 which resultsin-its beingmounted for free rotationA withrthe chuck 30. TheV clamping of the gearG in the adaptor 32 also results inaccurate centering thereof so that itis in aposition-of denite radialclearance with respect to theapproximate locating lingers 76; Thus, when the spindle is'rotated thegear rotates therewith free froml contact with any portion ofthelocatingA xture and thus, is adapted for free -rotation'with thechuck 30. The meshed engagement between the gear G and the tool Tresults in rotation of the tool. The machining operation, as is wellunderstood, isjaccomplished by. a slow traverseofthecutterV slide in-adirection parallel to the axis of the gear spindle to extend thefinishing action of the tool longitudinally of the internal teeth of thegear.

It will be understood that with the foregoing arrangement, resharpeningof the cutter requires a compensating vertical adjustment of the knee 12both to position the cutter properly for the machining 'operation andalso to locate thermeshed work gear properly for advancement into thechuck. Y

- The present invention takes advantage of the fact that i it vispossible quickly and easily to place the work gear in properly rneshedrelation onthe exposed cutter and thereafter to feed the meshedgearand'cutter combination into the chuck. This is much simplerVandsafer than attempting to clamp the gear in the' 'chuck and thereafterto feed the Ycutter into properlymeshed relation therewith. This latteroperation requires accurate angular position of the cutter and anyfailure accompanied by relatively rapid traverse of the cutter towardthe gear may result in damage to the expensive cutter. Y

La the machines specifically described in the foregoing, means areprovided for positively rotating the work holder. The tool in this caseis'driven due to its meshing engagement with the work gear. It willof'course be understood that if desired', the work spindle maybe freelyrotatable and rotation imparted directly to the tool spindle.

It will also be understood that if desired, the approximate locator mayinclude forwardly extending lingers engageable with the outer surfacerather than the inner surface of the work gear as it is supported on thecutter, to prevent rocking of the work gear. Since this arrangementmight in some cases interfere with operation of theV clamping elements48, the means on the approximate locator engageable with the outersurface of thework gear may befassociated with a work clamping chuckincluding radially movable clamping members.

The drawings and' the foregoing specification constitute a descriptionof the improved method ofl and apparatus for internal gear shaving insuch full, clear',` concise and exact terms as to enable any personkrskilled in the art to` practice the iriventiom-the scope of which isindicated-by the appended claims. Y

A. What I claim as 'my invention is:

l. The method of loading internal'gearsinto a gear finishing machineyhaving an external gear-like tool re-A quired to roll in mesh with thegear during the finishing operation, which comprises positioningthe tooloutwardly v from a gear-receiving chuck, placing the internal gear onthe Atool in mesh therewith and suspended-thereon, therethe gear in thechuck while it remains in mesh with the tool.

2. The method of loading internal gears into a gear iinishing machinehaving an external gear-like tool required to roll in mesh with the gearduring the finishing operation, which comprises positioning the tooloutwardly from a gear-receiving chuck, placing the internal gear on thetool in mesh therewith and suspended thereon, supporting the gearagainst rocking on the tool, moving the tool into the chuck to bring thegear into the chuck, and clamping the gear in the chuck while it remainsin mesh with the tool.

3. The method of loading internal gears into a gear finishing machinehaving an external gear-like tool required to roll in mesh with the gearduring the finishing operation, which comprises positioning the tooloutwardly from a gear-receiving chuck, placing the internal gear on thetool in mesh therewith and suspended thereon, supporting the gearagainst rocking on the tool, moving the tool into the chuck to bring thegear into the chuck, moving the gear while still in mesh with the toolinto fully seated position in the chuck and into a position of freerotation in meshed relation with the tool.

4. An internal gear linishing machine comprising a base, work supportmeans thereon comprising a pot chuck, a tool slide on said base movabletoward and away from the open end of said chuck, a tool spindle housingon said slide, a tool spindle in said spindle housing extending beyondone end thereof and adapted to rotatably support a gear-like toolthereon, an approximate locator carried by said housing engageable withan internal gear placed in mesh with and suspended on the tool on saidspindle while the tool is in position to support the internal gearexterior to said pot chuck, means for advancing the tool slide toposition the gear in said chuck, and clamping means in said chuckoperable to clamp the internal gear in said chuck while it remains inmesh with said tool.

5. An internal gear finishing machine comprising a base, work drivemeans thereon comprsing a pot chuck, a tool slide on said base movabletoward and away from the open end of said chuck, a tool spindle housingon said slide, a tool spindle in said spindle housing extending beyondone end thereof and adapted to rotatably support a gear-like toolthereon, an approximate locator carried by said housing engageable withthe inner surfaces of an internal gear placed in mesh with and suspendedon the tool on said spindle, means for advancing the tool slide toposition the gear in said chuck, and clamping means in said chuckoperable to draw the gear partly away from said locator out of contacttherewith and clamp the internal gear in said chuck while it remains inmesh with said tool.

6. An internal gear nishng machine comprising a base, work drive meansthereon comprising a po. chuck, a tool slide on said base movable towardand away from the open end of said chuck, a tool spindle housing on saidslide, a tool spindle in said spindle housing extending beyond one endthereof and adapted to rotatably support a gear-like tool thereon, anapproximate locator carried by said housing having a pair of lingersloosely engageable within an internal gear suspended on the tool in meshtherewith to prevent rocking ot the gear thereon, means i'or advancingthe tool slide to position the gear in said chuck, and clamping means insaid chuck operable to clamp the internal gear in said chuck while itremains in mesh with said tool.

7. An internal gear linishing machine comprising a base, work drivemeans thereon comprising a pot chuck, a tool slide on said base movabletoward and away from the open end of said chuck, a tool spindle hot singon said slide, a tool spindle in said spindle housing extending beyondone end thereof and adapted to rotatably support a gear-like toolthereon, an approximate locator carried by said housing having a pair oifingers loosely engageable within an internal gear suspended on the toolin mesh therewith to prevent rocking of the gear thereon, means foradvancing the tool slide to position the gear in said chuck, andclamping means in said chuck operable to clamp the internal gear in saidchuck while it remains in mesh with said tool, said fingers being inclearance with respect to the gear when it is clamped in said chuck.

8. An internal gear finishing machine comprising a base, work drivemeans thereon comprising a pot chuck, a tool slide on said base movabletoward and away from the open end of said chuck, a tool spindle housingon said slide, a tool spindle in said spindle housing extending beyondone end thereof and adapted to rotatably support a gear-like toolthereon, an approximate locator carried by said housing having a pair offingers loosely engageable within an internal gear suspended on the toolin mesh therewith to prevent rocking of the gear thereon and a spring toengage the bottom inner surface of the gear, means for advancing thetool slide to position the gear in said chuck, and clamping means insaid chuck operable to clamp the internal gear in said chuck while itremains in mesh with said tool.

9. An internal gear nishing machine comprising a base, work drive meansthereon comprising a pot chuck, a tool slide on said base movable towardand away from the open end of said chuck, a tool spindle housing on saidslide, a tool spindle in said spindle housing extending beyond one endthereof and adapted to rotatably support a gear-like tool thereon, anapproximate locator carried by said housing having a pair of lingersloosely engageable within an internal gear suspended on the tool in meshtherewith to prevent rocking of the gear thereon and a spring to engagethe bottom inner surface of the gear, means for advancing the tool slideto position the gear in said chuck, and clamping means in said chuckoperable to clamp the internal gear in said chuck while it remains inmesh with said tool, the clamping means including movable membersengageable with the gear and operable to draw it out of contact withsaid spring.

10. An internal gear finishing machine comprising a rotary work supportincluding an open-ended pot chuck and a tool support, including a rotaryspindle, means for relatively moving said supports to move a gear-liketool from a working position within said chuck to a loading positionspaced outwardly from the open end of said chuck, locator means on saidtool support engageable with an internal gear suspended in mesh on atool on said spindle to guide the gear into said chuck as the tool ismoved therein, and clamp means in said chuck for cfamping the geartherein.

11. An internal gear finishing machine comprising a rotary work supportincluding an open-ended pot chuck and a tool support, including a rotaryspindle, means for relatively moving said supports to move a gear-liketool on said spindle from a working position within said chuck to aloading position spaced outwardly from the open end of said chuck,locator means on said tool support engageable with an internal gearsuspended in mesh on a tool on said spindle to guide the gear into saidchuck as the tool is moved therein, and clamp means in said chuck forclamping the gear therein, said locator means and said clamp means beingconstructed to provide for movement of the gear out of contact with saidlocator means as it is clamped by said clamp means in said chuck.

References Cited in the le of this patent UNITED STATES PATENTS1,022,761 Stvanek Apr. 9, 1912 1,036,994 Garvin et al. Aug. 27, 19121,989,652 Drummond Jan. 29, 1935 2,280,045 Miller Apr. 14. 19422,733,072 Hohwart et al. lan. 3l, 1956 2,736,238 Moncriel Feb. 28, 19562,773,426 Fowler et al. Dec. 1l, 1956

